Internet Engineering Task Force (IETF) P. Cain
Request for Comments: 5901 The Cooper-Cain Group, Inc.
Category: Standards Track D. Jevans
ISSN: 2070-1721 The Anti-Phishing Working Group
July 2010
Extensions to the IODEF-Document Class for Reporting Phishing
Abstract
This document extends the Incident Object Description Exchange Format
(IODEF) defined in RFC 5070 to support the reporting of phishing
events, which is a particular type of fraud. These extensions are
flexible enough to support information gleaned from activities
throughout the entire electronic fraud cycle -- from receipt of the
phishing lure to the disablement of the collection site. Both simple
reporting and complete forensic reporting are possible, as is
consolidating multiple incidents.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5901.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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RFC 5901 IODEF Phishing Extensions July 2010Appendix C. Sample Phishing Report ...............................46C.1. Received Lure ............................................46C.2. Phishing Report ..........................................481. Introduction
Deception activities, such as receiving an email purportedly from a
bank requesting you to confirm your account information, are an
expanding attack type on the Internet. The terms "phishing" and
"fraud" are used interchangeably in this document to characterize
broadly-launched social engineering attacks in which an electronic
identity is misrepresented in an attempt to trick individuals into
revealing their personal credentials (e.g., passwords, account
numbers, personal information, ATM PINs, etc.). A successful
phishing attack on an individual allows the phisher (i.e., the
attacker) to exploit the individual's credentials for financial or
other gain. Phishing attacks have morphed from directed email
messages from alleged financial institutions to more sophisticated
lures that may also include malware.
This document defines a data format extension to the Incident Object
Description Exchange Format (IODEF) [RFC5070] that can be used to
describe information about a phishing or other type of fraudulent
incident. Sections 2 and 3 of this document provides an overview of
the terminology and process of a phishing event. Section 4
introduces the high-level report format and how to use it. Sections
5 and 6 describe the data elements of the fraud extensions. The
appendices include an XML schema for the extensions and a few example
fraud reports.
The extensions defined in this document may be used to report the
social engineering victim lure, the collection site, credential
targeted ("spear") phishing, broad multi-recipient phishing, and
other evolving Internet-based fraud attempts. Malware and other
malicious software included within the lure may also be included
within the report.
1.1. Why a Common Report Format Is Needed
To combat the rise in malicious activity on the Internet, service
providers and investigative agencies are sharing more and more
network and event data in a coordinated effort to identify
perpetrators and compromised accounts, coordinate responses, and
prosecute attackers. As the number of data-sharing parties
increases, the number of party-specific tools, formats, and
definitions multiply rapidly until they overwhelm the investigative
and coordination abilities of those parties.
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RFC 5901 IODEF Phishing Extensions July 2010
By using a common format, it becomes easier for an organization to
engage in this coordination as well as correlation of information
from multiple data sources or products into a cohesive view. As the
number of data sources increases, a common format becomes even more
important, since multiple tools would be needed to interpret the
different sources of data. A big win in a common format is the
ability to automate many of the analysis tasks and significantly
speed up the response and prosecution activities.
1.2. Processing of Exchanged Data Not Defined
While the intended use of this specification is to facilitate data
sharing between parties, the mechanics of this sharing process and
its related political challenges are out of scope for this document.
1.3. Relation to the INCH IODEF Data Model
Instead of defining a new report format, this document defines an
extension to [RFC5070]. The IODEF defines a flexible and extensible
format and supports a granular level of specificity. These phishing
and fraud extensions reuse subsets of the IODEF data model and, where
appropriate, specify new data elements. Leveraging an existing
specification allows for more rapid adoption and reuse of existing
tools in organizations. For clarity, and in order to eliminate
duplication, only the additional structures necessary for describing
the exchange of phishing and e-crime activity are provided.
2. Terminology Used in This Document
Since many people use different but similar terms to mean the same
thing, we use the following terminology in this document.
a. Phishing
The overall process of identifying victims, contacting them via a
lure, causing a victim to send a set of private credentials to a
collection site, and storing those credentials is called
phishing.
b. Fraud Event
A fraud event is the combination of phishing and subsequent
fraudulent use of the private credentials.
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RFC 5901 IODEF Phishing Extensions July 2010
c. Lure
A lure is the decoy used to trick a victim into performing some
activity, such as providing their private credentials. The lure
relies on social engineering concepts to convince the victim that
the lure is genuine and its instructions should be followed. A
lure includes a pointer or link to a collection site.
d. Collection Site
The website, email box, SMS number, phone number, or other place
where a phished victim sends their private credentials for later
fraudulent use by a criminal.
e. Credentials
A credential is data that is transferred or presented to
establish either a claimed identity or the authorizations of a
system entity. Many websites require a user name and password --
combined, they are a credential -- to access sensitive content.
f. Message
Although primarily email, a lure can be transported via any
messaging medium, such as instant messages, Voice over IP (VoIP),
or text via an SMS service. The term "message" is used as a
generic term for any of these transport mediums.
2.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
3. Interesting Fraud Event Data
Before defining the structure of the IODEF extensions, we identify
the "interesting" data in phishing and other fraudulent activities.
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RFC 5901 IODEF Phishing Extensions July 20103.1. The Elements of a Phishing/Fraud Event
+-----------+ +------------------+
| Fraudster |<---<-- | Collection Site |<---O--<----<----+
+----+------+ +------------------+ | |
| | |
| +--|-----+ ^
| | Sensor | Credentials
| +-|------+ |
| +---------------+ | +-------+
\--->--| Attack Source |--Lure--->-----O------> | User/ |
+---------------+ |Victim |
+-------+
Figure 3.1. The Components of Internet Fraud
Internet-based phishing and fraud activities are normally comprised
of at least six components:
1. The phisher, fraudster, or party perpetrating the fraudulent
activity. Most times this party is not readily identifiable.
2. The attack source -- the source of the phishing email, virus,
trojan, or other attack -- is masked in an enticing manner.
3. The lure used to trick the victim into responding.
4. The user, victim, or intended target of the fraud or phish.
5. The credentials, personal data, or other information the victim
has surrendered to the phisher.
6. The collection site, where the victim sends their credentials or
personal data if they have been duped by the lure of the phisher.
This may be a website, mailbox, phone operator, or database.
If we take a holistic view of the attack, there are some additional
components:
o The sensor -- the means by which the phish is detected. This
element may be an intrusion detection system, firewall, filter,
email gateway, or human analyst.
o A forensic or archive site (not pictured), where an investigator
has copied or otherwise retained the data used for the fraud
attempt or credential collection.
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RFC 5901 IODEF Phishing Extensions July 20103.1.1. Fraudulent Activity Extensions to the IODEF-Document
Fraud events are reported in a fraud activity report, which is an
instance of an XML IODEF-Document Incident element with added
EventData and AdditionalData elements. The additional fields in the
EventData specific to phishing and fraud are enclosed in a
PhraudReport XML element. Fraudulent activity may include multiple
emails, instant messages, or network messages, scattered over various
times, locations, and methodologies. The PhraudReport within an
EventData may include information about the email header and body,
details of the actual phishing lure, correlation to other attacks,
and details of the removal of the web server or credential collector.
As a phishing attack may generate multiple reports to an incident
team, multiple PhraudReports may be combined into one EventData
structure, and multiple EventData structures may be combined into one
incident report. One IODEF incident report may record one or more
individual phishing events and may include multiple EventData
elements.
This document defines new extension elements for the EventData IODEF
XML elements and identifies those required in a PhraudReport. The
appendices contain sample fraud activity reports and a complete
schema.
The IODEF Extensions defined in this document comply with Section 4,
"Extending the IODEF Format" in [RFC5070].
3.2. Useful Data Items in a Fraud Event
There are a number of subtle and non-obvious data to capture from a
fraud event that make the event analysis and correlation with other
events more useful. These data can be grouped into categories:
3.2.1. Data about the Lure
If a lure was presented as part of the fraud event, this category
includes the original received lure, the means by which the lure was
received (e.g., email, phone, or SMS), and the source addresses that
sent the lure. Other useful data includes DNS data about the lure
source, identification of any accompanying malware, and the brand
name defrauded.
3.2.2. Credential Collection Site Data
The collection site contains victim identifications, along with
copies of data supplied by the victims, such as account names or
numbers, passwords, dates of birth, etc. This category of useful
data includes these credentials, along with information about the
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RFC 5901 IODEF Phishing Extensions July 2010
collection site itself, such as its type, site DNS data, DNS
registrant data, and site physical location. The location and
registrant information is particularly important if law enforcement
assistance is expected. Additionally, an entire site archive can be
gathered to allow a collector on a shared website to be disabled
without impacting other users.
3.2.3. Detection Information
This is a non-obvious data category and contains data on how the lure
or collection site was detected. Understanding how the lure was
detected allows us to design and implement better detection systems.
3.2.4. Analysis Output
In an environment where time is critical, it is imperative that
analysis from one party can be reliably explained to and shared with
other investigative parties. This grouping includes data that an
investigator found interesting or could be useful to others.
4. Fraud Activity Reporting via IODEF-Documents
A fraud activity report is an instance of an XML IODEF-Document with
additional extensions and usage guidance, as specified in Section 4
of this document. These additional extensions are implemented
through the PhraudReport XML element.
As described in the following subsections, reporting fraud activity
has three primary components: choosing a report type, a format for
the data, and how to check the correctness of the format.
4.1. Fraud Report Types
There are three actions relating to reporting phishing events.
First, a reporter may *create* and exchange a new report on a new
event. Secondly, a reporter may *update* a previously exchanged
report to indicate new collection sites, site takedown information,
or related activities. Lastly, a reporter may have realized that the
report is in error or contains significant incorrect data and that
the prudent reaction is to *delete* the report.
The three types of reports are denoted through the use of the
ext-purpose attribute of an Incident element. A new report contains
an empty or a "create" ext-purpose value; an updated report contains
an ext-value value of "update"; a request for deletion contains a
"delete" ext-purpose value. Note that this is actually an advisory
marking for the report originator or recipient, as operating
procedures in a report life cycle are very environment specific.
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RFC 5901 IODEF Phishing Extensions July 20105. PhraudReport Element Definitions
A PhraudReport consists of an extension to the
Incident.EventData.AdditionalData element with a dtype of "xml". The
elements of the PhraudReport will specify information about the six
components of fraud activity identified in Section 3.1. Additional
forensic information and commentary can be added by the reporter as
necessary to show relation to other events, to show the output of an
investigation, or for archival purposes.
5.1. PhraudReport Structure
A PhraudReport element is structured as follows. The components of a
PhraudReport are introduced in functional grouping, as some
parameters are related and some elements may not make sense
individually.
+------------------+
| PhraudReport |
+------------------+
| STRING Version |<>--{0..1}--[ PhishNameRef ]
| ENUM FraudType |<>--{0..1}--[ PhishNameLocalRef ]
| STRING ext-value |<>--{0..1}--[ FraudParameter ]
| |<>--{0..*}--[ FraudedBrandName ]
| |<>--{1..*}--[ LureSource ]
| |<>--{1..*}--[ OriginatingSensor ]
| |<>--{0..1}--[ EmailRecord ]
| |<>--{0..*}--[ DCSite ]
| |<>--{0..*}--[ TakeDownInfo ]
| |<>--{0..*}--[ ArchivedData ]
| |<>--{0..*}--[ RelatedData ]
| |<>--{0..*}--[ CorrelationData ]
| |<>--{0..1}--[ PRComments ]
+------------------+
Figure 5.1. The PhraudReport Element
Relevant information about a phishing or fraud event is encoded into
six components as follows:
a. The PhishNameRef and PhishNameLocalRef elements identify the
fraud or class of fraud.
b. The LureSource element describes the source of the attack or
phishing lure, including host information and any included
malware.
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RFC 5901 IODEF Phishing Extensions July 2010
c. The DCSite element describes the technical details of the
credential collection site.
d. The OriginatingSensor element describes the means of detection.
The RelatedData, ArchivedData, and TakeDownInfo fields allow optional
forensics and history data to be included.
A specific phish/fraud activity can be identified using a combination
of the FraudType, FraudParameter, FraudedBrandName, LureSource, and
PhishNameRef elements.
5.2. Reuse of IODEF-Defined Elements
Elements, attributes, and parameters defined in the base IODEF
specification were used whenever possible in the definition of the
PhraudReport XML element. This specification does not introduce any
new variable types or encodings to the IODEF data model, but extends
the IODEF Contact and System elements.
The data model schema contains a copy of the iodef:System element.
Although we would like to just extend the System element, it is
defined in RFC 5070 with an unable-to-extend anonymous type, so we
copied the element, named its underlying type, and then generated the
extension to it.
Note: Elements that are imported from the base IODEF specification
are prefaced with an "iodef" XML namespace and are noted with the
section defining that element in [RFC5070]. Each element in a
PhraudReport is used as described in the following sections.
5.3. Element and Attribute Specification Format
The following sections describe the components of a PhraudReport XML
element. Each description is structured as follows.
1. A terse XML-type identifier for the element or attribute.
2. An indication of whether the element or attribute is REQUIRED or
optional. Mandatory items are noted as REQUIRED. If not
specified, elements are optional. Note that when optional
elements are included, they may REQUIRE specific sub-elements.
3. A description of the element or attribute and its intended use.
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RFC 5901 IODEF Phishing Extensions July 2010
Elements that contain sub-elements or enumerated values are further
sub-sectioned. Note that there is no "trickle-up" effect in
elements. That is, the required elements of a sub-element are only
populated if the sub-element is used.
5.4. Version Attribute
REQUIRED. STRING. The version shall be the value 0.06, to be
compliant with this document.
5.5. FraudType Attribute
REQUIRED. One ENUM. The FraudType attribute describes the type of
fraudulent activity described in this PhraudReport. The FraudType
chosen determines the value of the FraudParameter filed. This field
contains one of the following values:
1. phishing. The FraudParameter should be the subject line of the
phishing lure email or value of a lure IM or VoIP message. This
type is a standard phishing lure, usually sent as email, and is
intended to exploit the recipient's credentials for financial
gain.
2. recruiting. The FraudParameter is the subject line of the
recruit, or mule, email or message.
3. malware distribution. The FraudParameter is the email subject
line of the phishing email. This type of email phish does not
pose a risk of financial loss to the recipient, but lures the
recipient to an infected site.
4. fraudulent site. This identifies a known fraudulent site that
does not necessarily send spam but is used to show lures. The
FraudParameter may be used to identify the website.
5. dnsspoof. This choice does not have a related FraudParameter.
This value is used when a DNS system component responds with an
untrue IP address for the requested domain name due to either
cache poisoning, ID spoofing, or other manipulation of the DNS
system.
6. archive. There is no required FraudParameter for this choice,
although the FraudParameter of the original phish could be
entered. The data archived from the phishing server is placed in
the ArchivedData element.
7. other. This is used to identify not-yet-enumerated fraud types.
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RFC 5901 IODEF Phishing Extensions July 2010
8. unknown. This choice may have an associated FraudParameter. It
is used to cover confused cases.
9. ext-value. This choice identifies an unidentified FraudType.
The FraudType should be captured in the ext-value attribute.
5.5.1. ext-value Attribute
OPTIONAL. This STRING may be populated with a FraudType that has not
been predefined.
5.5.2. FraudParameter Element
Zero or one value of iodef:MLStringType. The contents of this
element are dependent on the FraudType choice. It may be an email
subject line, VoIP lure, link in an IM message, or a web URL. Note
that some phishers add a number of random characters onto the end of
a phish email subject line for uniqueness; reporters should delete
those characters before insertion into the FraudParameter field.
5.6. PhishNameRef Element
Zero or one value of iodef:MLStringType. The PhishNameRef element is
the common name used to identify this fraud event. It is often the
name agreed upon by involved parties or vendors. Using this name can
be a convenient way to reference the activity when collaborating with
other parties, the media, or engaging in public education.
5.7. PhishNameLocalRef Element
Zero or one value of iodef:MLStringType. The PhishNameLocalRef
element describes a local name or Unique-IDentifier (UID) that is
used by various parties before a commonly agreed-upon term is
adopted. This field allows a cross-reference from the submitting
organization's system to a central repository.
5.8. FraudedBrandName Element
Zero or more values of iodef:MLStringType. This is the identifier of
the recognized brand name or company name used in the phishing
activity (e.g., XYZ Semiconductor Corp).
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RFC 5901 IODEF Phishing Extensions July 20105.9. LureSource Element
REQUIRED. One or more values. The LureSource element describes the
source of the PhraudReport lure. It allows the specification of IP
addresses, DNS names, domain registry information, and rudimentary
support for the files that might be downloaded or registry keys
modified by the crimeware.
+-------------+
| LureSource |
+-------------+
| |<>--(1..*)--[ System ]
| |<>--(0..*)--[ DomainData ]
| |<>--(0..1)--[ IncludedMalware ]
| |<>--(0..1)--[ FilesDownloaded ]
| |<>--(0..1)--[ WindowsRegistryKeysModified ]
+-------------+
Figure 5.2. The LureSource Element
5.9.1. System Element
REQUIRED. One or more values of the iodef:System ([RFC5070],
Section 3.15). The system element describes a particular host
involved in the phishing activity. If the real IP address can be
ascertained, it should be populated. A spoofed address may also be
entered, and the spoofed attribute SHALL be set.
Multiple System elements may be used to identify the DNS name and IP
address(es) of the lure source.
5.9.2. DomainData Element
Zero or more element values. The DomainData element describes the
registration, delegation, and control of a domain used to source the
lure and can identify the IP address associated with the System
element URI. Capturing the domain data is very useful when
investigating or correlating events.
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RFC 5901 IODEF Phishing Extensions July 2010
The structure of a DomainData element is as follows:
+--------------------+
| DomainData |
+--------------------+
| |<>----------[ Name ]
| |<>--(0..1)--[ DateDomainWasChecked ]
| ENUM SystemStatus |<>--(0..1)--[ RegistrationDate ]
| ENUM DomainStatus |<>--(0..1)--[ ExpirationDate ]
| |<>--(0..*)--[ Nameservers ]
| |<>--(0..1)--[ DomainContacts ]
+--------------------+
Figure 5.3. The DomainData Element
5.9.2.1. Name Element
REQUIRED. One value of iodef:MLStringType. The Name element
contains the host DNS name used in this event. Its value should be
the complete DNS host address; e.g., if an event targeted
www.example.com, the value would be www.example.com.
5.9.2.2. DateDomainWasChecked Element
Zero or one value of DATETIME. This element includes the timestamp
of when this domain data was checked and entered into this report, as
many phishers modify their domain data at various stages of a
phishing event.
5.9.2.3. RegistrationDate Element
Zero or one value of DATETIME. The RegistrationDate element shows
the date of registration for a domain.
5.9.2.4. ExpirationDate Element
Zero or one value of DATETIME. The ExpirationDate element shows the
date the domain will expire.
5.9.2.5. Nameservers Element
Zero or more values. These fields hold nameservers identified for
this domain. Each entry is a sequence of DNSNameType and iodef:
Address pairs, as specified below.
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RFC 5901 IODEF Phishing Extensions July 2010
+--------------------+
| Nameservers |
+--------------------+
| |<>----------[ Server]
| |<>--(1..*)--[ iodef:Address ]
+--------------------+
Figure 5.4. The Nameservers Element
The use of one Server value and multiple Address values is used to
note multiple IP addresses associated with one DNS entry for the
domain nameserver.
5.9.2.5.1. Server Element
One value of iodef:MLStringType. This field contains the DNS name of
the domain nameserver.
5.9.2.5.2. iodef:Address Element
One or more values of iodef:Address. This field lists the IP
address(es) associated with this Server element.
5.9.2.6. DomainContacts Element
REQUIRED. Choice of either a SameDomainContact or one or more
Contact elements. The DomainContacts element allows the reporter to
enter contact information supplied by the registrar or returned by
whois queries. For efficiency of the reporting party, the domain
contact information may be marked to be the same as another domain
already reported using the SameDomainContact element.
+----------------+
| DomainContacts |
+----------------+
| |<>--(0..1)--[ SameDomainContact ]
| |<>--(1..*)--[ Contact ]
+----------------|
Figure 5.5. The DomainContacts Element
5.9.2.6.1. SameDomainContact Element
REQUIRED. One iodef:MLStringType. The SameDomainContact element is
populated with a domain name if the contact information for this
domain is identical to that name in this or another report.
Implementors are cautioned to only use this element when the domain
contact data returned by a registrar or registry is identical.
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RFC 5901 IODEF Phishing Extensions July 20105.9.2.6.2. Contact Element
REQUIRED. One or more iodef:Contact elements. This element reuses
and extends the iodef:Contact elements for its components. Each
component may have zero or more values. If only the role attribute
and the ContactName component are populated, the same (identical)
information is listed for multiple roles.
+--------------------+
| Contact |
+--------------------+
| |<>----------[ iodef:ContactName ]
| |<>--(0..*)--[ iodef:Description ]
| ENUM role |<>--(0..*)--[ iodef:RegistryHandle ]
| |<>--(0..1)--[ iodef:PostalAddress ]
| ENUM restriction |<>--(0..*)--[ iodef:Email ]
| STRING ext-role |<>--(0..*)--[ iodef:Telephone ]
| ENUM type |<>--(0..1)--[ iodef:Fax ]
| STRING ext-type |<>--(0..1)--[ iodef:Timezone ]
| |<->----------[ AdditionalData ]
| | +<-> [ Confidence ]
+--------------------+
Figure 5.6. The Contact Element
Each Contact has optional attributes to capture the sensitivity and
role for which the contact is listed. Elements reused from [RFC5070]
are not discussed in this document.
5.9.2.6.2.1. Confidence Element
REQUIRED. ENUM. The Confidence element describes a qualitative
assessment of the veracity of the contact information. This
attribute is an extension to the iodef:Contact element and is defined
in this document. There are five possible Confidence values, as
follows.
1. known-fraudulent. This contact information has been previously
determined to be fraudulent, as either non-existent physical
information or containing real information not associated with
this domain registration.
2. looks-fraudulent. The contact information has suspicious
information included.
3. known-real. The contact information has been previously
investigated or determined to be correct.
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RFC 5901 IODEF Phishing Extensions July 2010
4. looks-real. The contact information does not arouse suspicion
but has not been previously validated.
5. unknown. The reporter cannot make a value judgment on the
contact data.
5.9.2.6.2.2. ext-role Attribute
REQUIRED. ENUM. The ext-role attribute is extended from the iodef:
ext-role attribute with values identified in RFC 3982 [RFC3982]. The
ext-value value of the role attribute should be used, with the
ext-role attribute value chosen from one of the following values:
1. billingContacts
2. technicalContacts
3. administrativeContacts
4. legalContacts
5. zoneContacts
6. abuseContacts
7. securityContacts
8. otherContacts
9. hostingProvider. This contact is the hosting provider of this
server. Although not in RFC 3982, it is useful in investigations
to note where the server is located and who operates it. Load-
balanced, multicast, or anycast servers may have multiple
hostingProvider contact entries.
5.9.3. SystemStatus Attribute
REQUIRED. ENUM. The SystemStatus attribute assesses a system's
involvement in this event. The value is chosen from this list:
1. spoofed. This domain or system did not participate in this
event, but its address space or DNS name was simply used by
another party.
2. fraudulent. The system is operated with fraudulent intentions,
e.g., the domain name is a homophone.
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RFC 5901 IODEF Phishing Extensions July 2010
3. innocent-hacked. The system was compromised by a third party and
used in this event.
4. innocent-hijacked. The IP address or domain name was
deliberately hijacked via BGP or DNS and used in this event to
source the lure or host the collection site.
5. unknown. No conclusions are inferred from this event.
5.9.4. DomainStatus Attribute
ENUM. The DomainStatus attribute describes the registry status of a
domain at the time of the report. The following enumerated list is
taken from the "domainStatusType" of [RFC3982]. An extra "unknown"
value was added in case the status is indeterminable.
1. reservedDelegation
2. assignedAndActive
3. assignedAndInactive
4. assignedAndOnHold
5. revoked
6. transferPending
7. registryLock
8. registrarLock
9. other
10. unknown
5.9.5. IncludedMalware Element
Zero or one value. The IncludedMalware element allows for the
identification and optional inclusion of the actual malware that was
part of the lure. The goal of this element is not to detail the
characteristics of the malware but rather to allow for a convenient
element to link malware to a phishing campaign.
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RFC 5901 IODEF Phishing Extensions July 2010
+------------------+
| IncludedMalware |
+------------------+
| |<>--(1..*)--[ Name ]
| |<>--(0..1)--[ ds:Reference ]
| |<>--(0..1)--[ Data ]
+------------------+
+-----------------------+
| Data |
+-----------------------+
| hexBinary XORPattern |
+-----------------------+
Figure 5.7. The IncludedMalware Element
5.9.5.1. Name Element
REQUIRED. One or more values of iodef:MLStringType. This field is
used to identify the lure malware by its known name. Unnamed malware
may be identified by a value of "unknown".
5.9.5.2. Reference Element
Zero or one value of the Reference. This optional field is used to
hold the algorithm identification and value of a hash computed over
the malware executable. This entire element is imported from
[RFC3275]. Implementations SHOULD support the use of SHA-1 [SHA] as
a DigestMethod.
5.9.5.3. Data Element
Zero or one value. The optional Data element is used to include the
lure malware, which is encoded as a hexBinary type and XORed with a
pattern to render it harmless.
5.9.5.3.1. XORPattern Attribute
One value of hexBinary. The Data element includes a 16-hexadecimal-
character XORPattern attribute to support disabling the included
malware to bypass anti-virus filters. The default value is
0x55AA55AA55AA55BB, which would be XORed with the malware datastring
to recover the actual malware.
Cain & Jevans Standards Track [Page 20]

RFC 5901 IODEF Phishing Extensions July 20105.9.6. FilesDownloaded Element
Zero or one value of a sequence of File elements.
+---------------------+
| FilesDownloaded |
+---------------------+
| |<>--(1..*)--[ File ]
+---------------------+
Figure 5.8. The FilesDownloaded Element
5.9.6.1. File Element
One or more values of iodef:MLStringType. The File element value is
the name of a file downloaded by this lure.
5.9.7. WindowsRegistryKeysModified Element
One or more values of the Key sequence. The contents of the
WindowsRegistryKeysModified element are sequences of Key elements.
+------------------------------+
| WindowsRegistryKeysModified |
+------------------------------+
| |<>--(1..*)--[ Key ]
+------------------------------+
+--------------+
| Key |
+--------------+
| |<>-----[ Name ]
| |<>-----[ Value ]
+--------------+
Figure 5.9. The WindowsRegistryKeysModified Element
5.9.7.1. Key Element
One or more sequences. The Key element is a sequence of Name and
Value pairs representing an operating system registry key and its
value. The key and value are encoded as in Microsoft .reg files
[KB310516].
Cain & Jevans Standards Track [Page 21]

RFC 5901 IODEF Phishing Extensions July 20105.9.7.1.1. Name Element
One STRING, representing the Windows Operating System Registry Key
Name. The value is encoded as in Microsoft .reg files, e.g.,
[HKEY_LOCAL_MACHINE\Software\Test\KeyName].
5.9.7.1.2. Value Element
One STRING, representing the value of the associated Key encoded as
in Microsoft .reg files, e.g., REG_BINARY:01.
5.10. OriginatingSensor Element
REQUIRED. The OriginatingSensor element contains the identification
and cognizant data of the network element that detected this fraud
activity. Note that the network element does not have to be on the
Internet itself (i.e., it may be a local Intrusion Detection System
(IDS)), nor is it required to be mechanical (e.g., humans are
allowed).
Multiple OriginatingSensor elements are allowed to support detection
at multiple locations.
+----------------------------+
| OriginatingSensor |
+----------------------------+
| ENUM OriginatingSensorType |<>------------[ DateFirstSeen ]
| |<>--(1..*)----[ iodef:System ]
+----------------------------+
Figure 5.10. The OriginatingSensor Element
The OriginatingSensor requires a type value and identification of the
entity that detected this fraudulent event.
5.10.1. OriginatingSensorType Attribute
REQUIRED. ENUM. The value is chosen from the following list,
categorizing the function of this sensor:
1. web. A web server or service detected this event.
2. webgateway. A proxy, firewall, or other network gateway detected
this event.
3. mailgateway. The event was detected via a mail gateway or
filter.
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RFC 5901 IODEF Phishing Extensions July 2010
4. browser. The event was detected at the user web interface or
browser-type element.
5. ispsensor. The event was detected by an automated system in the
network, such as Intrusion Detection System, Intrusion Protection
System, or other Internet Service Provider device.
6. human. A non-automated system (e.g., a human, manual analysis,
etc.) detected this event.
7. honeypot. The event was detected by receipt at a decoy device.
8. other. The detection was performed via a non-listed method.
5.10.2. DateFirstSeen Element
REQUIRED. DATETIME. This is the date and time that this sensor
first saw this phishing activity.
5.10.3. iodef:System Element
REQUIRED. One or more values of iodef:System. This is
identification information (such as the IP version, IP address, etc.)
of the entity that detected this event. The ability to identify
multiple detectors is supported.
5.11. The DCSite Element
Zero or more DCSite elements. The DCSite captures the type,
identifier, location, and other pertinent information about the
credential gathering process, or data collection site, used in the
phishing incident. The data collection site is identified by four
elements: the type of collector, the network location, information
about its DNS domain, and a confidence factor. Further details about
the domain, system, or owner of the DCSite can be inserted into the
DomainData sub-element.
If the DCSite element is present, a value is required. Multiple
DCSite elements are allowed to indicate multiple collection sites for
a single collector. Multiple URLs pointing to the same DNS entry can
be identified with multiple SiteURL elements.
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RFC 5901 IODEF Phishing Extensions July 2010
+--------------+
| DCSite |
+--------------+
| ENUM DCType |<>--+--------[ SiteURL ]
| | +--------[ Domain ]
| | +--------[ EmailSite ]
| | +--------[ System ]
| | +--------[ Unknown ]
| |<>--(0..*)---[ iodef:Node ]
| |<>--(0..1)---[ DomainData ]
| |<>--(0..1)---[ iodef:Assessment ]
+--------------+
Figure 5.11. The DCSite Element
5.11.1. DCType Attribute
REQUIRED. ENUM. The DCType attribute identifies the method of data
collection as determined through the analysis of the victim computer,
lure, or malware. This attribute coupled with the DCSite content
identifies the data collection site.
1. web. The user is redirected to a website to collect the data.
2. email. The victim sends an email with credentials enclosed.
3. keylogger. Some form of keylogger is downloaded to the victim.
4. automation. Other forms of automatic data collection, such as
background Object Linking and Embedding (OLE) automation, are
used to capture information on the user's machine.
5. unspecified.
5.11.2. DCSite Values
REQUIRED. The DCSite element contains the IP address, URL, email
site, or other identifier of the credential or data collection site.
The Domain choice may be used to identify entire "phishy" domains
like those used for the RockPhish and related malware. Each DCSite
element also includes a confidence attribute to convey the reporter's
assessment of their confidence that this DCSite element is valid and
involved with this event. The confidence value is a per-DCSite
value, as multiple-site data collectors may have different confidence
values.
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RFC 5901 IODEF Phishing Extensions July 2010
The DCSite element is a choice of:
1. SiteURL. One value of iodef:MLStringType. This choice supports
URIs and other web-based identifiers.
2. Domain. One value of iodef:MLStringType. This choice allows the
entry of a DNS domain name.
3. EmailSite. One value of iodef:MLStringType. This choice
includes an email address if the site used email communications.
4. iodef:Address. One value of iodef:Address element. This choice
is used to capture the IP address of a site.
5. Unknown. One value of iodef:MLStringType. The unknown entry is
used for exceptions to the preceding choices.
5.11.2.1. Confidence Attribute
One value of INTEGER. The confidence attribute is a value between 0
and 100, representing the reporter's certainty that this is a genuine
phishing site. A value of 0 represents a false positive; a value of
100 signifies that the reporter has independently verified this site.
5.11.3. iodef:Node Element
Zero or more values of iodef:Node. This element is used to identify
the IP address(es) or DNS names associated with the DCSite element
value.
5.11.4. DomainData Element
Zero or one value of DomainData (Section 5.9.2). This element allows
for the identification of data associated with the data collection
site.
5.11.5. iodef:Assessment Element
Zero or one value of iodef:Assessment. This element is used to
designate different confidence levels of multiple-site data
collectors.
5.12. TakeDownInfo Element
Zero or more TakeDownInfo elements. This element identifies the
agent or agency that performed the removal, DNS domain disablement,
or ISP-blockage of the phish or fraud collector site. A PhraudReport
may have multiple TakeDownInfo elements to support activities where
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RFC 5901 IODEF Phishing Extensions July 2010
multiple takedown activities are involved on different dates. Note
that the term "agency" is used to identify any party performing the
blocking or removal, such as ISPs or private parties, and not just
government entities.
The TakeDownInfo element allows one date element with multiple
TakeDownAgency and Comment elements to support operations using
multiple agencies.
+-------------------+
| TakeDownInfo |
+-------------------+
| |<>---(0..1)--[ TakeDownDate ]
| |<>---(0..*)--[ TakeDownAgency ]
| |<>---(0..*)--[ TakeDownComments ]
+-------------------+
Figure 5.12. The TakeDownInfo Element
5.12.1. TakeDownDate
Zero or one value of DATETIME. This is the date and time that
takedown of the collector site occurred.
5.12.2. TakeDownAgency
Zero or more iodef:MLStringType elements. This is a free-form string
identifying the agency, corporation, or cooperative that performed
the takedown.
5.12.3. TakeDownComments
Zero or more iodef:MLStringType elements. A free-form field to add
any additional details of this takedown effort or to identify parties
that assisted in the effort at an Internet Service Provider (ISP),
Computer Emergency Response Team (CERT), or DNS registry.
Cain & Jevans Standards Track [Page 26]

RFC 5901 IODEF Phishing Extensions July 20105.13. ArchivedData Element
Zero or more values of the ArchivedData element are allowed.
+-------------------+
| ArchivedData |
+-------------------+
| ENUM type |<>---(0..1)--[ URL ]
| |<>---(0..1)--[ Comments ]
| |<>---(0..1)--[ Data ]
+-------------------+
Figure 5.13. The ArchivedData Element
The ArchivedData URL element is populated with a pointer to the
contents of a data collection site, base camp (i.e., development
site), or other site used by a phisher. The ArchivedData Data
element may also include a copy of the archived data recovered from a
phishing system. This element will be populated when, for example,
an ISP takes down a phisher's website and has copied the site data
into an archive file.
There are four types of archives currently supported, as specified in
the type field.
5.13.1. type Attribute
REQUIRED. This parameter specifies the type of site data pointed to
by the ArchivedData URL element, from the following list:
1. collectionsite. The archive is a set of files from the
collection site.
2. basecamp. The contents of a criminal development site are
included in the archive.
3. sendersite. The archive is a set of files or data from a
phishing lure sending site.
4. credentialInfo. The included archives are recovered private
credentials.
5. unspecified. The archive contents do not fit into one of the
above categories and will be described in the DataComments
element.
Cain & Jevans Standards Track [Page 27]

RFC 5901 IODEF Phishing Extensions July 20105.13.2. URL Element
Zero or one value of anyURL. As the archive of an entire site can be
quite large, the URL element points to an Internet-based server where
the actual content of the site archive can be retrieved. Note that
this element just points out where the archive is and does not
include the entire archive in the report. This is the URL where the
archive file is located.
5.13.3. Comments Element
Zero or one value of iodef:MLStringType. This field is a free-form
area for comments on the archive and/or URL.
5.13.4. Data Element
Zero or one value of xs:Base64Binary. This field contains a base64-
encoded version of the data described in the comment field above.
5.14. RelatedData Element
Zero or more values of anyURI. This element allows the listing of
other websites or net sites that are related to this incident (e.g.,
victim site, etc.).
5.15. CorrelationData Element
Zero or more values of iodef:MLStringType. Any information that
correlates this incident to other incidents can be entered here.
5.16. PRComments Element
Zero or one value of iodef:MLStringType. This field allows for any
comments specific to this PhraudReport that do not fit in any other
field.
5.17. EmailRecord Element
This element supports the inclusion of the actual email message
received as a phishing lure. Inclusion of the actual mail message is
supported by two methods: either the message may be included as one
large string, or the header and body components may be dissected and
included as a series of strings.
Cain & Jevans Standards Track [Page 28]

RFC 5901 IODEF Phishing Extensions July 2010
+--------------------+
| EmailRecord |
+--------------------+
| |<>--------------[ EmailCount ]
| |<>--(0..1)------[ EmailMessage ]
| |<>--(0..1)------[ EmailComments ]
+--------------------+
Figure 5.14. The EmailRecord Element
5.17.1. EmailCount Element
REQUIRED. INTEGER. This field enumerates the number of email
messages identified in this record as detected by the reporter.
5.17.2. EmailMessage Element
Zero or one value of iodef:MLStringType. The entire SMTP mail
message -- rfc822 header followed by body, as specified in [RFC5322]
-- should be inserted as one large text string. In some communities,
this combination is known as the message contents and full headers.
5.17.3. EmailComments Element
Zero or one value of iodef:MLStringType elements. This field
contains comments or relevant data not placed elsewhere about the
phishing email.
6. Mandatory IODEF and PhraudReport Elements
A report about fraud or phishing requires certain identifying
information that is contained within the standard IODEF Incident data
structure and the PhraudReport extensions. The following table
identifies attributes required to be present in a compliant
PhraudReport to report phishing or fraud. The required attributes
are a combination of those required by the base IODEF element, as
shown in Figure 6.1, and those required by this document, shown in
Figure 6.2. Attributes identified as required SHALL be populated in
conforming phishing activity reports.
Cain & Jevans Standards Track [Page 29]

RFC 5901 IODEF Phishing Extensions July 2010
The reporting party is encouraged to provide more than just the
minimally required data elements about an event in a PhraudReport.
The additional information may be volatile and not recoverable in the
future, and may be useful in answering investigation questions or in
performing correlation with other reported events.
7. Security Considerations
This document specifies a format for encoding a particular class of
security incidents appropriate for exchange across organizations. As
merely a data representation, it does not directly introduce security
issues. However, it is guaranteed that parties exchanging instances
of this specification will have certain concerns. For this reason,
the underlying message format and transport protocol used MUST ensure
the appropriate degree of confidentiality, integrity, and
authenticity for the specific environment.
Organizations that exchange data using this document are URGED to
develop operating procedures that document the following areas of
concern.
7.1. Transport-Specific Concerns
The critical security concerns are that phishing activity reports may
be falsified or the PhraudReport may become corrupt during transit.
In areas where transmission security or secrecy is questionable, the
application of a digital signature and/or message encryption on each
report will counteract both of these concerns. We expect that each
exchanging organization will determine the need, and mechanism, for
transport protection.
7.2. Using the iodef:restriction Attribute
In some instances, data values in particular elements may contain
data deemed sensitive by the reporter. Although there are no
general-purpose rules on when to mark certain values as "private" or
"need-to-know" via the iodef:restriction attribute, the reporter is
cautioned not to apply element-level sensitivity markings unless they
believe the receiving party (i.e., the party they are exchanging the
event report data with) has a mechanism to adequately safeguard and
process the data as marked. For example, if the PhraudReport element
is marked private and contains a phishing collector URL in the
DCSite/SiteURL element, can that URL be included within a block list
distributed to other parties? No guidance is provided here except to
urge exchanging parties to review the IODEF and PhraudReport
documents to decide on common marking rules.
Cain & Jevans Standards Track [Page 31]

RFC 5901 IODEF Phishing Extensions July 20108. IANA Considerations
This document uses URNs to describe XML namespaces and XML schemas
conforming to a registry mechanism described in [RFC3688].
Registration request for the IODEF phishing namespace:
URI: urn:ietf:params:xml:ns:iodef-phish-1.0
Registrant Contact: See the "Authors' Addresses" section of this
document.
XML: None.
Registration request for the IODEF phishing extension XML schema:
URI: urn:ietf:params:xml:schema:iodef-phish-1.0
Registrant Contact: See the "Authors' Addresses" section of this
document.
XML: See Appendix A, "Phishing Extensions XML Schema", of this
document.
9. Contributors
The extensions are an outgrowth of the Anti-Phishing Working Group
(APWG) activities in data collection and sharing of phishing and
other e-crimeware. (The APWG has no relationship to an IETF working
group.)
This document has received significant assistance from members of the
IETF INCH working group and two groups addressing the phishing
problem: members of the APWG and participants in the Financial
Services Technology Consortium's Counter-Phishing project. A special
thanks goes to the hardy people who supplied valuable feedback after
using this format to report phishing.
10. References10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3275] Eastlake, D., Reagle, J., and D. Solo, "(Extensible
Markup Language) XML-Signature Syntax and Processing",
RFC 3275, March 2002.
Cain & Jevans Standards Track [Page 32]

RFC 5901 IODEF Phishing Extensions July 2010
<xs:attribute name="type" use="required">
<xs:simpleType id="ArchivedDataType.type">
<xs:restriction base="xs:NMTOKENS">
<xs:enumeration value="collectionsite"/>
<xs:enumeration value="basecamp"/>
<xs:enumeration value="sendersite"/>
<xs:enumeration value="credentialInfo"/>
<xs:enumeration value="unspecified"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:complexType>
</xs:schema>
Appendix B. Example Virus Report
This section shows a received electronic mail message that included a
virus in a zipped attachment and a report that was generated for that
message.
B.1. Received Email
From: support@example.com
Sent: Friday, June 10, 2005 3:52 PM
To: someone@example.com
Subject: Account update
To: someone@example.com
Date: Sun, 10 June 2005 3:52:44 +0200
We would like to inform you that we have released a new version of our
Customer Form. This form is required to be completed by all customers.
Please follow these steps:
1.Open the form at http://www.example.com/customerservice/cform.php
<http://www.2.example.com/customerservice/cform.php
&amp;email=(someone@example.com)> .
2.Follow given instructions.
Thank you,
Our Support Team
Cain & Jevans Standards Track [Page 43]

RFC 5901 IODEF Phishing Extensions July 2010
X-EN-OrigIP: 192.0.2.1
X-EN-OrigHost: unknown
Company<http://www.example.com/images/company_logo.gif>
<http://www.example.com/images/pixel.gif>
<http://www.example.com/images/pixel.gif>
<http://www.example.com/images/pixel.gif>
Account Update Request
Dear Example. member:,
You are receiving this notification because company is required by
law to notify you, that you urgently need to update your online
account statement, due to high risks of fraud intentions.
The updating of your example account can be done at any time by
clicking on the link shown below
http://www.example.com/cgi-bin/webscr?cmd=_login-run
<http://192.0.2.41:8080/.cgi-bin/.webscr/.secure-login/%20/%20/.paypal.com/index.htm>
Once you log in, update your account information.
After updating your account, click on the History sub tab of your
Account Overview page to see your most recent statement.
If you need help with your password, click the Help link that is at
the upper righthand side of the company website. To report errors
in your statement or make inquiries, click the Contact Us link in the
footer on any page of the company website, call our Customer Service
center at (999) 555-0167, or write us at:
Company, Inc.
P.O. Box 0
Anytown, MA 00000
Sincerely,
Big Example Company
<http://www.example.com/images/dot_row_long.gif>
Cain & Jevans Standards Track [Page 47]

RFC 5901 IODEF Phishing Extensions July 2010
The updating of your example account can be done at any time by
clicking on the link shown below
&lt;a href="http://192.0.2.41:8080/.cgi-bin/.webscr/.secure-
login/%20/%20/.example.com/index.htm">
http://www.example.com/cgi-bin/webscr?cmd=_login-run &lt;/a>
Once you log in,update your account information.
After updating your account click on the History sub tab of your
Account Overview page to see your most recent statement.
If you need help with your password, click the Help link which is at
the upper right hand side of the company website. To report errors in
your statement or make inquiries, click the Contact Us link in the
footer on any page of the company website, call our Customer Service
center at (999) 555-0167, or write us at:
Company, Inc.
P.O. Box 0
Anytown, MA 00000
Sincerely,
Big Example Company
&lt;img src="http://www.example.com/images/dot_row_long.gif">
</phish:EmailMessage>
</phish:EmailRecord>
<phish:DCSite DCType="web">
<phish:SiteURL>http://190.0.2.41:8080/.cgi-bin/.webscr/.secure-
login/%20%20/.example.com/index.htm</phish:SiteURL>
<phish:DomainData DomainStatus="assignedAndActive"
SystemStatus="unknown">
<phish:Name>bad.example.com</phish:Name>
<phish:DateDomainWasChecked>2006-06-14T13:05:00-05:00
</phish:DateDomainWasChecked>
<phish:RegistrationDate>
2000-12-13T00:00:00</phish:RegistrationDate>
<phish:Nameservers>
<phish:Server>ns1.example.net</phish:Server>
<Address>192.0.2.18</Address>
</phish:Nameservers>
</phish:DomainData>
</phish:DCSite>
</phish:PhraudReport>
</AdditionalData>
</EventData>
</Incident>
</IODEF-Document>
Cain & Jevans Standards Track [Page 50]